Handling Soap timeouts in PHP
1) In case of timeout, PHP throws a SoapFault exception with faultcode="HTTP" and faultstring="Error Fetching http headers".
2) In my opinion, the best way to distinguish between a timeout error and web service issues is by looking at the faultcode and faultstring members of the SoapFault class.
In particular, the faultcode element is intended for use by software to provide an algorithmic mechanism for identifying the fault.
As you can also read in a comment of the PHP manual, there is no method to read the faultcode property, so you have to access it directly (eg. $e->faultcode), because the getCode() method does not work.
The SOAP 1.1 Spec defines four possible values for the faultcode field:
- VersionMismatch: The processing party found an invalid namespace for the SOAP Envelope element
- MustUnderstand: An immediate child element of the SOAP Header element that was either not understood or not obeyed by the processing party contained a SOAP mustUnderstand attribute with a value of "1"
- Client: The Client class of errors indicate that the message was incorrectly formed or did not contain the appropriate information in order to succeed. For example, the message could lack the proper authentication or payment information. It is generally an indication that the message should not be resent without change.
- Server: The Server class of errors indicate that the message could not be processed for reasons not directly attributable to the contents of the message itself but rather to the processing of the message. For example, processing could include communicating with an upstream processor, which didn't respond. The message may succeed at a later point in time.
In addition to those codes, PHP uses the HTTP code for identifying the errors happening at the protocol level (eg.: socket errors); for example, if you search for add_soap_fault in the ext/soap/php_http.c source code you can see when some of these kind of faults are generated.
By searching for the add_soap_fault and soap_server_fault functions in the PHP SOAP extension source files, I've built the following list of PHP SoapFault exceptions:
HTTP----Unable to parse URLUnknown protocol. Only http and https are allowed.SSL support is not available in this buildCould not connect to hostFailed Sending HTTP SOAP requestFailed to create stream??Error Fetching http headersError Fetching http body: No Content-Length: connection closed or chunked dataRedirection limit reached: abortingDidn't recieve an xml documentUnknown Content-EncodingCan't uncompress compressed responseError build soap requestVersionMismatch---------------Wrong VersionClient------A SOAP 1.2 envelope can contain only Header and BodyA SOAP Body element cannot have non Namespace qualified attributesA SOAP Envelope element cannot have non Namespace qualified attributesA SOAP Header element cannot have non Namespace qualified attributesBad RequestBody must be present in a SOAP envelopeCan't find response dataDTD are not supported by SOAPencodingStyle cannot be specified on the BodyencodingStyle cannot be specified on the EnvelopeencodingStyle cannot be specified on the HeaderError cannot find parameterError could not find "location" propertyError finding "uri" propertylooks like we got "Body" with several functions calllooks like we got "Body" without function calllooks like we got no XML documentlooks like we got XML without "Envelope" elementMissing parametermustUnderstand value is not booleanSoapClient::__doRequest() failedSoapClient::__doRequest() returned non string valueUnknown Data Encoding StyleUnknown ErrorDataEncodingUnknownMustUnderstand--------------Header not understoodServer------Couldn't find WSDLDTD are not supported by SOAPUnknown SOAP versionWSDL generation is not supported yet3) To simulate the timeout condition, try with the following code:
soapclient.php
<?phpini_set('default_socket_timeout', 10);$client = new SoapClient(null, array( 'location' => "http://localhost/soapserver.php", 'uri' => "http://localhost/soapserver.php", 'trace' => 1 ));try { echo $return = $client->__soapCall("add",array(41, 51));} catch (SoapFault $e) { echo "<pre>SoapFault: ".print_r($e, true)."</pre>\n"; //echo "<pre>faultcode: '".$e->faultcode."'</pre>"; //echo "<pre>faultstring: '".$e->getMessage()."'</pre>";}?>soapserver.php
<?phpfunction add($a, $b) { return $a + $b;}sleep(20);$soap = new SoapServer(null, array('uri' => 'http://localhost/soapserver.php'));$soap->addFunction("add");$soap->handle();?>Notice the sleep call in the SoapServer.php script with a time (20) longest than the time (10) specified for the default_socket_timeout parameter in the SoapClient.php script.
If you want to simulate a service unavailability, you could for example change the location protocol from http to https in the soapclient.php script, assuming that your web server is not configured for SSL; by doing this, PHP should throw a "Could not connect to host" SoapFault.
Looks like default_socket_timeout is not taken into account when making SOAP calls over HTTPS:
Bug open at the time of writing. As a comment on the blog post Robert Ludwick referenced in a deleted answer Timing Out PHP Soap Calls (21 Oct 2009; by Published by Robert F. Ludwick) points out, the workaround the post discusses (overriding SoapClient::__doRequest() with a curl request) works around this bug also.
Another related bug is:
The code mentioned in the blog post has undergone some changes and can be found in it's latest form with support of HTTP authentication here on Github:
In any case, the workaround shouldn't be needed any longer as this problem has been fixed in the PHP SOAPClient extension.
To deal with timeouts in the service
$client = new SoapClient($wsdl, array("connection_timeout"=>10));// SET SOCKET TIMEOUTif(defined('RESPONSE_TIMEOUT') && RESPONSE_TIMEOUT != '') { ini_set('default_socket_timeout', RESPONSE_TIMEOUT);}